Shielding apparatus for a light waveguide plug arrangement

ABSTRACT

A shielding apparatus is connected in contacting fashion to a shielding ply of a backplane printed circuit board of a module chassis, is provided with contact openings at which the shielding apparatus can be contacted with metallic guide sleeves onto which plug connectors for light waveguides coming from the outside can be plugged. Specifically, contact openings are provided with star-shaped slots between which resiliently deflectable, radially resilient contact tongues are formed which engage an outside surface of the guide sleeves.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a shielding apparatus for anarrangement of a pluggable connection of at least one light waveguide toa module chassis.

2. Description of the Prior Art

Related shielding designs have been disclosed, for example, by WO94/12900. In accord therewith, a housing in which metallic guidesleeves, that project through a clearance of a backplane printed circuitboard, are accepted is attached to the inside of the backplane printedcircuit board of a module chassis. A plug connector from a lightwaveguide coming from the outside can be plugged onto the guide sleeves.The plug connector includes a metallic union nut that can be screwed tothe guide sleeve. The backplane printed circuit board includes ashielding ply at its outside onto which a metallic member is applied; ametallic shielding sleeve being screwed thereto. The union nut and theshielding sleeve are extended beyond the plug.

In this region, the shielding sleeve includes spring tongues that havebeen cut free and that lie against a smooth-surfaced contact section ofthe union nut. The diameter of the clearance is of such a size that theguide sleeve or, respectively, the plug connector do not laterally touchthe backplane printed circuit board in order to avoid a distortion ofthe plug connector arrangement. The clearance is electromagneticallyclosed and adequately shielded by the chimney-like shieldingarrangement.

The present invention is therefore directed to an alternative shieldingarrangement for the above-described configuration wherein themanufacturing and assembly outlay for such shielding arrangement may begreatly reduced.

SUMMARY OF THE INVENTION

Pursuant to the present invention, a guide sleeve can be of such alength that it not only projects into the clearance, but also throughit. The shielding apparatus bridges the distance between the guidesleeve and the shielding ply over a short path. It directly contactsboth the shielding ply and the guide sleeve so that intermediatecontacts are eliminated. The shielding apparatus can be formed simplyand cost-beneficially and requires little space; thus, simple assemblyis enabled. The plug connection is substantially easier to accesscompared to an arrangement having a shielding sleeve that can be screwedin. As a result, the distance between neighboring plug connectors can bereduced.

The lateral resilience of the contact opening relative to the guidesleeve prevents lateral forces from being exerted thereon. Such forces,for example, can bend the slotted guide sleeve and deteriorate theoptical connection quality.

The clearance can, for example, be formed as a through-plated boreconnected to the shielding ply. The sleeve-shaped shielding apparatuscan, for example, be composed of highly conductive elastomeric plasticand can include an inner, all around rib. The shielding apparatus isintroduced into the bore and contacts the guide sleeve with theresilient rib. The lateral resilience of the shielding apparatus alsoyields a dependable contacting along the circumference of the shieldingsleeve.

In an embodiment, the shielding apparatus can be punched in a simple wayfrom a contact sheet of, for example, brass, bronze, Gennan silver orchrome-nickel steel. The circumference of the guide sleeve can includesharp-edged ribs pointing in longitudinal direction; for example, in theform of a knurl that presses itself into the smoothly circular contactopening. This yields a number of reliable contact locations thatelectromagnetically close the remaining gaps. The shielding apparatuscan be connected to the shielding ply by soldering, for example. Theshielding apparatus can be kept so thin that it does not impede theinstallation of other component parts.

In another embodiment, when the guide sleeve is plugged through, thecontact tongues of the shielding apparatus are obliquely deflected outof the material plane so as to conform with resilient stress against,for example, the cylindrical outside cladding of the guide sleeve. Thisyields a dependable contacting given great lateral resilience, whichenables a corresponding compensation of tolerances between the shieldingapparatus and the guide sleeve.

In a further embodiment, a single shielding apparatus is particularlyformed so as to contact a number of guide sleeves.

In another embodiment, the shielding apparatus is contacted with theshielding ply in a simple, clamping manner. A particular advantage ofsuch embodiment is that the shielding apparatus can be deliveredpre-mounted at the housing, so that any and all added outlay in theassembly of the module chassis is eliminated.

In yet a further embodiment, the shielding apparatus is centered at thehousing. The centering openings can be kept such that the shieldingapparatus clamps to them and is, thus, reliably held for final assembly.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the Detailed Description of thePreferred Embodiments and the Drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a portion of a module chassis with aplug connector for a light waveguide;

FIG. 2 shows parts of the assembly chassis according to FIG. 1, as wellas the shielding apparatus of the present invention, immediately beforeassembly; and

FIG. 3 shows the parts of FIG. 2 in a different perspective view afterassembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to FIG. 1, a module chassis (shown in simplified detail) forinsertable assemblies includes a backplane printed circuit board 1 towhose assembly side a housing 2 is secured. The housing 2 is providedwith receptacles 3 for guide sleeves 4 (FIG. 2). An insertable assembly5 includes a comer edge connector 6 having plug pins 7 connected tolight waveguides that can be plugged into the guide sleeves 4 of thehousing 2 with plug pins that are not visible here. Plug connectors 8for light waveguides can have their plug pins 16 individually pluggedinto the guide sleeves 4 at that side of the backplane printed circuitboard 1 lying opposite the housing 2.

According to FIGS. 2 and 3, the backplane printed circuit board 1 isprovided with cylindrical clearances 9 into which the guide sleeves 4project, with play, after assembly. At the side which meets the housing2, the backplane printed circuit board 1 is provided with a shieldingply 10 that is uncovered at least in the region of the housing 2. Ashielding apparatus which is formed as a shielding plate 11 ispositioned between the housing 2 and the shielding ply 10 and is clampedtherebetween in contacting fashion in the assembled condition. Theshielding plate 11 includes centering openings 12 with which it is fixedon correspondingly arranged centering pegs 13 of the housing 2.

The shielding plate 11 also is provided with contact openings 14 intowhich radially proceeding, narrow slots are arranged in star-shapedfashion. As a result, a number of individual contact tongues 15 areformed whose free ends point inward toward a center of the contactopening 14. The clearance between opposingly-positioned contact tongues15 (i.e., inside diameter of the contact opening 14) is narrower thanthe outside diameter of the guide sleeves 4 in the region of theshielding plate 11.

When joining the parts, the guide sleeves 4 pass through the contactopenings 14 of the shielding plate 11, wherein the contact tongues 15are deflected into the clearance and lie against the outside cladding ofthe guide sleeves 4 under spring tension. The resilient yielding of thecontact tongues 15 enables the compensation of positional deviationsbetween the shielding plate 11 and the guide sleeves 4 and also yields anumber of dependable contacts between the shielding plate 11 and theguide sleeves 4.

Although the present invention has been described with reference tospecific embodiments, those of skill in the art will recognize thatchanges may be made thereto without department from the spirit and scopeof the invention as set forth in the hereafter appended claims.

We claim:
 1. A shielding apparatus for a pluggable connectionarrangement of at least one light waveguide to a module chassis, whereinthe arrangement includes a metallic guide sleeve for a plug connector ofthe light waveguide, the guide sleeve projecting into a clearance of abackplane printed circuit board of the module chassis, the backplaneprinted circuit board including a shielding ply to which the shieldingapparatus may be contacted, the shielding apparatus comprising a shieldmember for shielding bridging of the interspace between the guide sleeveand the backplane printed circuit board, wherein the shield memberincludes a contact opening having a contactable circumferential edge forcontacting an outside cladding of the guide sleeve in transverselyresilient fashion.
 2. A shielding apparatus for a pluggable connectionarrangement of at least one light waveguide to a module chassis asclaimed in claim 1, wherein the shield member is formed as a thinshielding plate for covering the interspace such that the shieldingplate can be contacted flat with the shielding ply of the backplaneprinted circuit board, and wherein the contact opening is narrower thana diameter of the contacted outside cladding of the guide sleeve.
 3. Ashielding apparatus for a pluggable connection arrangement of at leastone light waveguide to a module chassis as claimed in claim 2, whereinthe shielding plate can be clamped between a housing and the shieldingply of the backplane printed circuit board, the housing havingreceptacles for the guide sleeves and being securable to a side of thebackplane printed circuit board which includes the shielding ply.
 4. Ashielding apparatus for a pluggable connection arrangement of at leastone light waveguide to a module chassis as claimed in claim 3, whereinthe shielding plate includes centering openings through which centeringpegs of the housing may project.
 5. A shielding apparatus for apluggable connection arrangement of at least one light waveguide to amodule chassis as claimed in claim 2, wherein the shielding plateincludes slots arranged in star-shaped fashion proceeding radiallyoutward from the contact opening between which contact tongues areformed which are deflectable out of a plane of the shielding plate suchthat inwardly directed, free ends of the contact tongues substantiallyform the contact opening.
 6. A shielding apparatus for a pluggableconnection arrangement of at least one light waveguide to a modulechassis as claimed in claim 2, wherein the shielding plate includes aplurality of contact openings for a plurality of guide sleevesneighboring one another.